This report covers the production of dry season rice, which was planted in November and harvested in April. Maize planting started in April.  Rainfall was slightly above average (+3%), while temperature  and solar radiation  were below the 15YA (TEMP -0.5°C, RADPAR -7%) . Potential biomass production was reduced  by 1%. NDVI  generally trended below the 5YA. The maximum vegetation condition index (VCIx) was relatively high at 0.94. The cropped arable land fraction (CALF) during the growing season was close to the average levels. The NDVI trend, in combination with a high VCIx and close to average CALF indicates slightly below-average production levels.

Regional analysis

The regional analysis covers   4 main agro-ecological zones (AEZ) of Thailand: Central double and triple-cropped rice lowlands,  North-eastern single-cropped rice region, South-eastern horticulture area, and Western and southern hill areas. The characteristics of rice planting are dependent on rice cultivation topology.

Indicators for the Central double and triple-cropped rice lowlands show a similar pattern as for the whole country: Temperature  and radiation were below average  (TEMP -0.5°C, RADPAR -9%)whilst the rainfall was higher than the 15YA by 12%. These weather factors led to a biomass increase (+14%). The fraction of cropped arable land (CALF) was unchanged and the maximum VCI was 0.93. According to the NDVI profile, the NDVI values were higher than in the previous year and close to the 5 year average during January to March 2021. In April, NDVI exceeded the 5YA.  The second rice production is forecasted to be higher than last year.

In the  North-eastern single-cropped rice region, temperature  and radiation were below average (-0.9ºC and -7% respctively) and rainfall increased by 23%. Estimated biomass was 10% below the 15YA.  VCIx was 0.95  and CALF was unchanged.  

Crop condition in the Western and southern hill area experienced drier than average conditions (RAIN -9%). Temperature was slightly cooler (-0.2ºC) and solar radiation was below average by 6%. Estimated biomass was higher by 3%.  VCIx was 0.93.

The South-eastern horticulture area  experienced above-average rainfall (RAIN +29%) while temperature and solar radiation were below average (TEMP -0.7%, RADPAR -11%), leading to a biomass reduction (BIOMSS -8%). 

Figure 1 Thailand's crop condition, crop calendar from January-April 2021

a) Crop phenology map of major crops

b) Phenology of major crops                                   c) Maximum VCI

d) Crop condition clustering map based on NDVI graph      

e) Crop classification

f) Rainfall profile                                               g) Temperature profile 

h) Crop condition development graph based on NDVI in the double and triple-cropped rice lowlands (left) and single-cropped rice North-eastern region (right) 

i) Crop condition development graph based on NDVI in the South-eastern horticulture area (left) and Western and southern hill areas (right)

Table 1 Thailand's agroclimatic indicators by sub-national regions, current values and departure of 15YA

Table 2 Thailand's cropped arable land fraction (CALF) and current maximum VCI values, January-April 2021